To find the squareroot of a number without using sqrt() functon

#include<iostream>
#include<conio.h>
using namespace std;

int main()
{ float g,r,c=0,n,pg;
cout<<"enter the number to find squareroot   ";
cin>>n;
        g=n/2; pg=n;                                          //g - guess  pg - previous guess
       while(g!=pg)                                           // when g==pg   , then g or pg is the square root
       {r=n/g;
       pg=g;
       g=(g+r)/2;
       }
cout<<"square root \t"<<g<<endl;
getch();       
}

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